The No Sugar diet is when you exclude all types of sugar (and often carbohydrates too) from your diet.

BDA Verdict:

Cutting down on free sugars, reducing the amount of sugar you add, and consuming fewer products already containing added sugar, in addition to being label aware is definitely a positive.

However, some versions of the No Sugar/Sugar Free Diet promote cutting out all sugar from your diet which is not only almost impossible, but would mean eliminating foods like vegetables, fruit, dairy products, nuts – leading to a less than healthy diet.

Also it is important to be aware of some substitutes these diet plans recommend like agave, palm sugar, maple syrup or honey, as these are actually just free sugars in another form and a huge contradiction. It’s not about a single food or nutrient, we advocate a whole diet approach.

2. The All-Kale And Chewing Gum Diet

Celebrity Link:

Jake Gyllenhaal reportedly followed this diet to shed weight for a film role.

What’s it all about?

There isn’t much to this one, as all you can eat is kale salad and chewing gum.

BDA Verdict:

This diet is extreme, socially isolating, unbalanced, hard to sustain and potentially harmful. An actor would be carefully monitored and supervised to shed weight for a role.

Many people get drawn in by so called "super foods" but no one food can provide all the nutrients you need. These foods are not a magic bullet, neither does balanced nutrition work by a "good" food cancelling out other poor dietary and lifestyle choices.

Nothing is wrong with kale, but if that is all you consume all day, every day, then problems will arise - it’s all about balance, a healthy relationship with food (not obsession) and variety.

3. Bulletproof diet

Celebrity Link:

Harry Styles and Shailene Woodley have reportedly followed this diet.

What’s it all about?

This quirky diet plan includes a daily "Bulletproof Coffee" which is essentially a black coffee with 2 tablespoons butter, and 1 tablespoons MCT oil added, totting up at around 400kcal per cup. Foods are classified as bulletproof, suspect or kryptonite with rules on timing of meals.

BDA Verdict:

While the idea of minimising alcohol and processed food is positive, the classification of foods is at odds with health recommendations and lacks evidence. Time restricted eating is also at odds with many lifestyles.

The negative of the recommended Bulletproof Coffee is that consuming 400-plus calories from one beverage provides a lot of energy but few nutrients from a drink, rather than individuals choosing food and drink with more nutritional content for the same calorie value.

4. The Super Elixir

Celebrity Link:

Elle McPherson is the co-founder and creative director of this product.

What’s it all about?

The Super Elixir is a food supplement aiming to change body tissue from an acidic to an alkaline state. It comes in the form of a green powder and contains just over 45 ingredients including a number of powdered fruits and vegetables, sweeteners, several Chinese herbs and some digestive enzymes.

The recommended dose is 2 teaspoons (or 10g) per day meaning a month’s supply could set you back £96 (£96 for 300g plus caddy/£62.50 for 300g pouch).

BDA Verdict:

How much?! The benefits that this costly powder claims to provide can easily be obtained from fruit and vegetables and a balanced diet, without the hefty price tag.

Moreover our bodies are naturally capable of regulating acidity levels. Why not save between £750-£1152 per year, spend it on some delicious fruit and vegetables and a splurge on a "Super" holiday instead!

5. TrimSecrets

Celebrity Link:

Baroness Michelle Mone OBE, founder of lingerie brand Ultimo and life peer in the House of Lords and Chanelle Hayes (former Big Brother star) have reportedly followed this plan.

What’s it all about?

Trim Secrets is a pill which claims to suppress appetite whilst boosting the metabolism, allegedly aiding both men and women to lose weight when combined with the Trim Secrets 5 stage diet plan.

The diet plan includes a balanced diet of 1500 calories per day along with a Trim Secrets capsule taken three times a day before each meal, 1.5 litres of water daily, regular exercise and avoiding stress.

BDA Verdict:

By consuming 1,500 calories per day, most individuals should lose weight regardless of whether they are taking this pill, and that’s no secret. The pill has echoes of the grapefruit diet and includes guarana which is high in caffeine yet states it’s caffeine free. Beware of pills and potions and make sure you know exactly what you are buying and taking.

Speaking about these and other fad diets, Sian Porter, consultant dietitian and spokesperson for the BDA, said: "The bottom line is, if it sounds too good to be true, then it probably is.

"If you have to pay out for a DVD or book or product that will unlock the secrets of losing weight, this can be a good indicator that the only pounds you will be losing will be out of your wallet.

"Maybe it’s not as exciting but the truth is if you do want to lose some weight do it by eating a healthy, balanced diet that you can stick to, watch your portion sizes and be physically active. Think of it as a marathon approach to achieving your goals as opposed to a sprint approach.

"Aim to make permanent changes to your diet and lifestyle that are sustainable for you in the long term, not someone else’s lifestyle, nor abandoned by the end of January."